Dark screen: broken inverter or CCFL backlight?

I have a Dell Inspiron 4150 whose screen has gone dark. I can faintly see the image, and using an external monitor works, so I'm assuming it's the LCD inverter or CCFL backlight that's gone bad. I'm guessing it's the inverter since the screen is completely black, no light at all, and it's a bit soon for a CCFL to burn out?

 

It sound like an inverter or backlight. Only one way to find out and its cheaper to replace the inverter first.

 

I am also going to say the inverter too. I replaced an inverter on my uncle's laptop with the same symptoms(very dim screen+external LCD worked fine) and it worked perfectly and as optomos mentioned, its the cheaper option.

 

Yes I agree with change invert only is cheap it easy to replace the black light if you go change the ccfl tube you have take apart monitor or replace the whole panel and the tub is dam small and break easy

http://www.j-right.com/html/ccfl_lcd_backlighting.htm

http://www.j-right.com/images/lcd/l_3.jpg

that a picture tube they snap very easly

 

I took the notebook apart. I have an Ambit J07I037.05 inverter and an IDTech ITXG76H screen. I see a bunch of J07I037 inverters on eBay, one of which is a .05 and the rest are different... revisions? It probably doesn't matter so long as it's a J07I037 series?

 

The J07I037.02 inverter arrived today, presumably older than the .05 original. I swapped it in and the screen works now... for several minutes. It'll cut out every once in a while but using Fn-F8 to cycle between the LCD and external display will bring it back. The external display always works when enabled. Suffice it to say that I'm confused. Any ideas?

 

Well, after I installed Windows and the ATI video drivers fired up, everything appears to be fine? No more weirdness. I flashed in the latest BIOS for good measure. I'll test it some more before I pass it along.

 

Oh geeze, everything was working fine for over a week and now the inverter's going bad again. Or something's trying to kill it. Any ideas? Should I try replacing the CCFL next?

Edit: According to this page:

Screen inverter replacement. Fixing laptop backlight problem.

I'm going to guess that the replacement inverter I bought was marginal to begin with. It was definitely a pull, not a new part. Sound right?

 

ask to get a different one, that yours is deffective, and if the new one doesn't work, than maybe you should try changing the ccfl, but its kinda hard, and its really easy to break.

 

Well, I ordered a new inverter from another vendor which is unfortunately shipping from Shanghai. If I get a working used replacement for my broken inverter before then, great, but I'm outside of the return period so I don't know if they'll cooperate.

 

You guys are going to love this. I finally give up and go to replace the backlight and it turns out that the wire on one end of the backlight had broken off. It made just enough of a connection to sometimes work. ARRRGH! Must have been a bad soldering job to begin with.

So now I've got a pile of inverters and the old backlight that probably work just fine.

BTW, changing the backlight is a PITA. Much, much more involved than just changing the inverter.

 

Yup I Agree with you back light is pain to change also solder thouse wire are not fun if you get one with out plug on it

Glad you got work I have keep that mind next time I have notebook with back light that is radom It silly some time how you think that it issue like tube or invert some time you never think try easy stuff like bad connections